A rough import, the markup of this article must be changed before translation can begin. Prime, Safe and Cycling

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Author : David Bogert

Published :

Time To Read :
6 minutes
Difficulty : Level 8

Excerpt :

Seachem Prime and Safe water conditioners do NOT help anything during cycling. Prime, Safe and Cycling Prime, Safe and Cycling

Prime and Safe are two water conditioners made by Seachem. The marketing department at Seachem has made a series of false marketing claims for these two products. This article examines one of those claims.

Note that I admit I am decidedly biased against the Seachem Company. I can’t help it. The amount of “pseudoscientific bedazzlement” they put out on ALL their products is just nauseating.  They mix real science in with simply impossible “snake oil” claims in a manner which is very misleading to “newbies” in the hobby. And they have threatened to sue me for “libel”. So the dislike is mutual.

The claim examined by this article is:


False Claim #2, Prime and Safe used during cycling won’t affect the cycle time.


The Technician on the Seachem Test site say about fish in cycling:

Dose Prime every 48 hours as needed to detoxify the ammonia in the tank, and keep the fish safe”.

And you will find that a good 90% of social media absolutely believes this to be good advice. Be forewarned that you will find yourself in the minority if you are publicly skeptical of this advice.  This 90% of social media is wrong. And 90% of the people on social media who read this article will not change their mind at all about Seachem Prime. They either will not believe the testing described below or they will find a perceived fault with the testing which, in their minds, invalidates the testing.

Using Prime and Safe during cycling will only slow the cycling process slightly. Prime and Safe are sodium dithionite. This is a reducing agent. Beneficial bacteria are “autotrophic” bacteria which use only chemicals as food, namely oxygen, ammonia and carbon dioxide. They take the oxygen and oxidize the ammonia to nitrite to create energy and they use the carbon dioxide to build their structure with proteins and carbohydrates.

Oxidation is interfered with by reducing agents (oxidation is the opposite of reduction in chemistry).  So beneficial bacteria can’t do their chemical processes in the presence of sodium dithionite. This was confirmed by testing. But note that because the dithionite is so dilute the negative effect is barely noticeable

Mikrogeophagus ramirezi Gold Ram
Mikrogeophagus ramirezi Gold Ram

Test Abstract

A test was run to see the effect of Seachem Prime and Stability regimen on time to cycle. The test showed using the Seachem Stability and Prime regimen increased the time to completion of cycling by 12 days.

Note that this test was deliberately kept quite simple so that anyone can easily duplicate it if they want to. A rigorous scientific test under laboratory conditions cannot be replicated by any hobbyist so that was not done. This test was not designed to be published in some science journal. But the significant difference in the test results makes the conclusions unmistakable and very valid, even if the science is not as rigorous as some would like.

Image of a tropical fish Glass Catfish
Glass Catfish

Test Equipment:

  • Home Depot five gallon buckets
  • 100 grams BASF ammonium chloride dissolved in one gallon distilled water
  • air pump and air lines
  • mini sponge filters

Test Procedure:

Six buckets were set up with reverse osmosis water. The water was naturally about 6.8 in pH 0 KH after sitting for a week to stabilize.

  • Three buckets had nothing done to them (the “controls”) with 2 ppm ammonia added daily.
  • Three buckets were set up with 6.8 water and Stability and Prime used in them per the directions of Seachem with 2 ppm ammonia added daily.

The buckets were then cycled. The buckets were then tested every day for ammonia and nitrite.

Parachromis nicarguensis
Parachromis nicarguensis


Defining zero (technically it is less than or equal to 0.25 ppm) ammonia and nitrite for two days (two readings) as being cycled, the following results were obtained:

This showed an average of 12 days added to the cycle time by using Prime and Stability. This is probably due to the fact that Seachem Prime is a reducing agent. Beneficial bacteria are autotrophs which oxidize ammonia to nitrate. Oxidation in chemistry is the opposite of reduction. So a reducing agent such as Prime will interfere with and slow down the beneficial bacteria.

image of an aquarium fish Melanochromis auratus, female
Melanochromis auratus, female

In addition bacteria in a bottle products like Seachem Stability did not do too well in testing.  Three tests were run on eleven popular bacteria-in-a-bottle products (seven of these were replicated twice for accuracy). Ten other treatments were used. The first two tests had a phosphate fertilizer added at the beginning of the cycling.

In the first two tests Black Kow composted cow manure, brown gunk from an aquarium filter and garden soil (packaged soil from the store is sterilized and thus useless) took 8 to 14 days to cycle, the commercial “bacteria-in-a-bottle” products and the four controls (no treatment) took 26 to 46 days to cycle. Surprisingly a third test showed that the addition of phosphate fertilizer is particularly important if one is cycling with ammonia

Bacteria in a bottle Test Results
Bacteria in a bottle Test Results

This test can be found at the link below:

2.8. Testing Of Bacteria In a Bottle Products


Protomelas taeniolatius OB Red Empress
Protomelas taeniolatius OB Red Empress
What SeaChem Says

What is really ludicrous about all this is that Seachem put up on their website a typical cycle they had tested using Seachem Stability and Seachem Prime. The test took 31 days to cycle. Yes, you read that right:


Seachem’s Own Cycling Test of Prime and Stability took 31 days


Now the test chart is no longer on their site as someone realized they were contradicting themselves with this test and its data. Interesting how marketing works.

Cycling with Prime and Stability
Cycling with Prime and Stability PER SEACHEM
Variabilichromis moorii
Variabilichromis moorii

The author must emphasis here that Prime and Safe are perfectly safe to use with fish and are both effective and inexpensive ways to neutralize chlorine or chloramine in tap water. The author’s research has ONLY shown Prime and Safe do not even temporarily “detoxify” or “bind” ammonia, nitrite, or nitrate.

Other False Claims

In addition to the false claim that Prime and Safe helps in cycling an aquarium, Seachem goes on to make the following false claims about Prime and Safe:

All of these claims are nothing more than snake oil marketing hype with no more validity than the late night commercials for hair loss products or virility enhancing pills. To go to an article proving each claim false simply click on the link on the false claim. All of these claims are proven false by testing delineated in each of the articles.


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